world.launch.py
代码语言：javascript复制import os
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import ExecuteProcess, DeclareLaunchArgument
from launch_ros.actions import Node
from launch.substitutions import LaunchConfiguration
# this is the function launch system will look for
def generate_launch_description():
robot_name = 'mobot'
world_file_name = 'mobot_room.world'
# full path to urdf and world file
world = os.path.join(get_package_share_directory(robot_name), 'worlds', world_file_name)
urdf = os.path.join(get_package_share_directory(robot_name), 'urdf', 'mobot.urdf')
# read urdf contents because to spawn an entity in
# gazebo we need to provide entire urdf as string on command line
xml = open(urdf, 'r').read()
# double quotes need to be with escape sequence
xml = xml.replace('"', '\"')
# this is argument format for spwan_entity service
spwan_args = '{name: "mobot", xml: "' xml '" }'
# create and return launch description object
return LaunchDescription([
# start gazebo, notice we are using libgazebo_ros_factory.so instead of libgazebo_ros_init.so
# That is because only libgazebo_ros_factory.so contains the service call to /spawn_entity
ExecuteProcess(
cmd=['gazebo', '--verbose', world, '-s', 'libgazebo_ros_factory.so'],
output='screen'),
# tell gazebo to spwan your robot in the world by calling service
ExecuteProcess(
cmd=['ros2', 'service', 'call', '/spawn_entity', 'gazebo_msgs/SpawnEntity', spwan_args],
output='screen'),
])
